Test-circuits.



F. N REEVES. TEST cmcuns. APPLICATION FILED MAR-2,1915.

L1 @Yfig Patented June 20, 1916.

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96? FI wink /V. Reeves WW W *1; is VFW FRANK N. REEVES, 0F NEWARK, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 WESTERN ELECTRIC COMPANY, INCORPORATED, A. CORPORATION 01 NEW YORK.

TEST-CIRCUITS.

Specification of Letters Patent,

Patented June 20', 191%..

Application filed March 2, 1915. Serial No. 11,586.

To all whom it may concern:

,Be it known that I, FRANKN. Rnnvns, a citizen of the United States, residing at Newark in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Test-Circuits, of which the following is a full,- clear, concise, and exact description.

This invention relates tovline selection and more particularly to the circuits by means of which a selector switch finds and connects itself to a desired one of a group of lines. The lines may be of any kind whatever, the only requisite being that busy potential be supplied to the test contacts of, the undesired lines of a group. In the present embodiment this busy potential will be supplied by connecting the test contacts to ground, although obviously the ground and battery connections of the test circuits may be reversed. The testing circuits herein disclosed have been found especially satisfactory in selecting an idle one from a group of trunks.

One of the objects of the invention is the provision of test circuits for use with switches which hunt in groups, whereby a switch is prevented from causing a line to test busy before it has seized said line, and thus the passing over of the desired line by seeking switches is prevented.

Another object of the invention is the provision of circuits of this character in which the probability of double connections or the connection of a plurality of switches to the same line is reduced to a minimum.

A further object of the invention is the provision of circuitsvwhereby testing may take place with certainty and at high speed.

In the drawings, only so much of the circuits are disclosed as will be useful in obtaining a clear understanding of the test cir cnits and their operation.

The switch illustrated is of the panel type and may be ofv a character such as shown in Patent No. 1,123,696, although obviously any other switch of the same general type may be employed, that is, any switch which.

employs an operating magnet which is continuously energized during the movement of the switch and in which a centering interrupter brush is also provided.

The sequence switch shown in the drawof brushes 2.

ings may be of the structure such as shown 1 therefore represent the positions in which.

the sequence switch may stop.

As the two switches shown in the drawing represent switches of the same group and are thcreforeidentical both in function and operation, the circuits of only the switch at the left will be described in detail, and correspondii'ig parts in the. switch and circuits at the right will be indicatedby corresponding reference characters primed.

In the drawings, 1 represents a switch shaft to which is secured one or more sets Fixed to the shaft 1 is an interrupter brush 3 adapted to traverse the conducting segment of an interrupter 4. The brush 8 is arranged to engage-a conducting scgment at all times except when the brushes of the set 2 are centrally positioned on a set of contacts in theterm'inal bank 5. Secured to the shaft 1, at the lower end thereof, isan elevating bar 6' adapted to be forced into engagement with the power drum 7 by means of the idler pulley 8, carried by the armature of the clutch or motor magnet 9.

We will now assume that in the process of setting up a call the sequence switches have been advanced in any usual manner to position 6, in which position a circuit will be completed from battery through the right winding of test relay 10, sequence switch contact 11 (6) to ground. Relay 10 is energized and completes a circuit from battery through sequence switch motor magnet 12-, contact 13 (6), front contact and armature of relay 10, to ground. The sequence switch thereupon moves from position 6 to position 7. In position 7 a holding circuit is completed for relay 10 through the right winding thereof, sequence switch contact 11.-

(7), brush 3 and bottom segment of inter- V cuit isalso completed from battery, through right winding of the test relay.

clutch magnet 9, sequence switch contact 14 (7), front contact and armature of relay 10, to ground. The clutch magnet 9 is energized and through the idler pulley 8 forces the bar 6 into engagement with the rotating friction drum 7, and the brushes of set 2 are moved along the contacts in the bank 5. By any desired means the test contacts of undesired lines will be supplied with ground potential.

We will now assume that the contacts in the bank 5 are connection circuit or trunk .contacts, and that the first six trunks in the group are busy and are, therefore connected 'to ground. When the brushes of set 2 are centrally positioned on the first or lowermost set of contacts, the interrupter brush 3 will be positioned on an insulating segment and the circuit through the right winding of relay 10 will be broken. However, at this time a circuit will extend from battery through the left winding of relay 10, its left contact and armature, test brush 15 and the contact engaged thereby, to ground, thus insuring that the test relay 10 will remain energized, and hence the circuit of the clutch magnet will remain closed until the interrupterbrush 3 again engages a conducting segment of the interrupter 4.

The shaft 1- will continue to move upward, the holding circuit for relay 10 being alternately completed through the test brush 3 and the test contacts of the undesired lines, which under the present assumption are busy trunks, and the interrupter brush 8 and conducting segment of the in terrupter 4. When, however, the brushes of set 2 engage the contacts of an idle trunk (which we will assume is the upper one in the drawing), no ground potential will be found on the test contact thereof, and the.

circuit through the left winding of test re lay 10 will be interrupted. The circuit through the right winding, however, will be maintained until the brushes of the set 2 have been centrally positioned on the con tacts 'of the set, when brush 3 will move on an insulating segment of the "interrupter 6, breaking the holding circuit through the The armatures of relay 10 will fall off and the left armature will open the holdin circuit through the left winding of said relay. The right armature in falling off will open the circuit of .the clutch magnet 9, and close at its bank contact a circuit from battery through sequence switch motor magnet 12, contact 16 (7), contact and back armature of relay 10 to ground,-whereupon the sequence switch will move to position 8.

Busy potential .may be supplied to the multiple test contacts of the selected circuit through sequence switch contact '17, and the back contact and left armature of relay 10.

In order to make the advantages of this invention more obvious, we will assume that at the time switch 1 centers on the contacts of an idle circuit, the test brush. of switch 1' has just engaged a multiple contact of said circuit and the interrupter brush 3 is still in electrical engagement with the grounded interrupter plate 4. With the present circuits the ground on interrupter brush 3' will not be so associated with the test contact of said circuit as to cause the circuit to test busy to switch 1, as would be the casea motor magnet therefor, an interrupter actuated in response to the movement of said switch, a test relay, a circuit for said magnet controlled by said relay, a pair of windings on said relay, parallel circuits for said windings, one being completed through the test brush of said switch and the other through said interrupter, and means for preventing the reenergization of said motor magnet after the desired line has been found.

3. In combination, a switch, a motor magnet therefor, an interrupter actuated in the movement of said switch, a relay, a circuit for said magnet extending through .front contacts of said relay, a pair of wind-' ings on said relay, and circuits for said windings, one of said circuits extending through a test brush of said switch and the other through said interrupter.

4. In combination, a switch, a motor magnet therefor, an interrupter actuated in the movement of said switch, a test relay 1 having a pair of energizing windings, a circuit for said motor magnet extending through front contacts of said relay, means for energizing said relay, and holding circuits for said windings, one of said circuits extending through a test brush of said switch and the other through said interrupter.

5. In combination, a switch, a motor magnet therefor, interrupter actuated 1n the movement of said switch, a test relay having a pair of energizing windings, a circuit for said motor magnet extending through front contacts of said relay, means for energizing said relay, and holding cirmemes cuits for said windings alternately completed in the movement of'said switch, one of said circuits extending through a test brush of said switch and the otherthrough said interrupter;

6. In combination, a switch, a motor magnet therefor, an interrupter actuated in the movement of said switch, a test relay having' apair of energizing. windings, a circuit for said motor magnet extending through front contacts of said relay, means for energizing said relay, and holding circuits for said windings alternately completed in the movement of said switch, one of said circuits extending through a front contact of said relay and a test brush of said switch and the other through said interrupter. i

7. In combination, a switch, a motor magnet therefor, an interrupter actuated in the movement of said switch, test contacts of circuits, a test brush for said switch arranged to traverse said contacts arelay having a pair of windings, a circuit for said motor magnet extending through front contacts of said relay, means for energizing said relay, and holdingcircuits for said relay windings, one being completed through said test brush and the test contacts of busy circuits, and the other through said interrupter.

8. In combination, a switch, a motor magnet therefor, an interrupter actuated in the movement of said switch, test cona relay having a pair of windings, a circuit tacts of circuits, a test brush for said switch arranged to traverse said contacts,

for said motor magnet extending through front contacts of said relay means for energizingsaid relay, and holding circuits for said relay windings, one being completed through said test brush and the test contacts of busy circuits, and the other through said interrupter while said brush is passing from the contact of one circuit to the contact of the next.

9. In combination, a switch, a motor magnet therefor, an interrupter actuated in the movement of said switch, a test brush for said switch, test contacts of circuits traversed by'said brush arelay having a pair of windings, a circuit for sald motor magnet extending through front contacts 01% said relay, means for energizing said relay, and

holding circuits for said relay windings, one

being completed through said test brush and the test contacts of busy circuits, and the other through said interrupter while said in the movement of said switch, test contacts of circuits, a test brush for said switch arranged to traverse said contacts, a relay having a pair of windings, a circuit for said motor magnet extending through front contacts of said relay, means for energizing said relay, and holding circuits for said relay windings, one being completed through a contact and armature of said relay, said test brush'and the test contacts of busy circuits, and the other through said interrupter while said brush is passing from the contact of one circuit to the contact of the next.

11. In combination, a switch, a motor magnet therefor, an interrupter actuated in the movement of said switch, a test brush for said switch, test contacts of circuits traversed by said brush, a relay having a pair of windings, a circuit for said motor magnet extending through front contacts of said relay, means for energizing said relay, and holding circuits for said relay windings, one being completed through a contact and-armature of said relay, said test brush and the test contacts of busy circuits, and the other through said interrupter while said brush is passing from a central position on the contact of one circuit to a corresponding position on the contact of the next circu1t, 5

In :witness whereof I hereunto subscribe E. EDLER, K. L. STAHL. 

